Y-system and functional dilogarithm identities

수학노트
http://bomber0.myid.net/ (토론)님의 2011년 2월 25일 (금) 12:25 판
둘러보기로 가기 검색하러 가기
introduction

 

 

five-term relation of dilogarithm

 

  1. f[{x_, y_, z_, w_}] := Simplify[(x - z)/(x - w)*(y - w)/(y - z)]
    A := Permutations[{0, 1, w, z}]
    Table[Limit[f[Ai], w -> \[Infinity]], {i, 24}]
    B := Subsets[{0, x*y, 1, y, z}, {4}]
    g[i_] := Table[
      Limit[f[n], z -> \[Infinity]], {n, Permutations[Bi]}]
    Table[f[Bi], {i, 1, 5}]
    Table[g[i], {i, 5}]

 

 

rank 2 example

\(y_{m-1}y_{m+1}=y_m+1\)

Start with two variables \(y_1,y_2\).

\(y_3y_1=y_2+1\). so \(y_3=\frac{y_2+1}{y_1}\)

\(y_2y_4=y_3+1 \)implies \(y_4=\frac{y_3+1}{y_2}=\frac{y_1+y_2+1}{y_1y_2}\)

\(y_3y_5=y_4+1\) implies \(y_5=\frac{y_4+1}{y_3}= \frac{y_1+1}{y_2}\) we are getting Laurent polynomials

\(y_4y_6=y_5\) implies \(y_6=\frac{y_5+1}{y_4}= \frac{\frac{y_1+1}{y_2}+1}{\frac{y_1+y_2+1}{y_1y_2}}=\frac{y_1(y_1+1)+y_1y_2}{y_1+y_2+1}=y_1\)

 

 

history

 

 

related items

 

 

encyclopedia

 

 

books

 

 

 

expositions

 

 

 

articles

 

 

question and answers(Math Overflow)

 

 

blogs

 

 

experts on the field

 

 

links